The purpose of this study is to investigate a new investigational anticancer drug, irinotecan (CPT-11) with patients whose brain cancer has progressively worsened despite previous therapy or inefficacy of standard treatment as a cure. CPT-11 is commercially available and indicated for treatment of several kinds of cancer; it is experimental for the purposes of treating brain cancer.The purpose of this study is to answer the following research questions:1. Is CPT-11 safe when given to patients with glioma? 2. What are the side effects of CPT-11 and how often do they occur? 3. How fast does CPT-11 and its breakdown products clear from the blood? 4. Can CPT-11 be effective in shrinking tumors when given to patients with glioma?